Display Device with Switchable Viewing Angle and Backlight Module Thereof

A display device with switchable viewing includes a backlight module and a display panel. The backlight module includes a light guide plate, first optical structures, a reflector, a first light source, and a second light source. The light guide plate includes a bottom surface, a light exit surface, a first light incident surface, and a second light incident surface. The display panel is disposed on the light exit surface. The first optical structures are disposed on the bottom surface and each includes a first inclined surface and a second inclined surface. The angle between the first inclined surface and the bottom surface is smaller than that between the second inclined surface and the bottom surface. Lights from the first light source and the second light source enter the light guide plate from the first light incident surface and the second light incident surface, respectively. After entering the light guide plate, the lights can be reflected by the first inclined surface or the second inclined surface, or be refracted by the first inclined surface or the second inclined surface to the underlying reflector and reflected by the reflector back to the light guide plate from the first inclined surface or the second inclined surface. Based on such a structure, by controlling the on/off state of the first light source and the second light source, the viewing angle of the display device is switchable.